The input range for ADL 5904 5910 and ADL 5511

Question

Hi, 
 We are interested to use ADL5904. ADL 5910 and ADL 5511. 
 We just want to know the input range for each IC, can you please confirm: 
 1. ADL5904 : minimum voltage 0V and maximum voltage 5.62V as specified on the datasheet. 
 2. ADL5910 : minimum voltage 0V and maximum voltage 5.62V as specified on the datasheet. 
 3. ADL5511: minimum voltage -2.8V and maximum voltage 2.8v or 5.6V[peak to peak] as specified on the datasheet. 
 If I follow the range above, I should not damage the IC right? In addition, my frequency input range is from 10 Hz to 10MHz. 
 Thanks

enash · Answer

There is a little more to it than that. Let's talk about ADL5904 and ADL5910 first as they are very similar parts. The data sheet says that the max input power is 25 dBm with the input ac coupled and with and external 82.5 ohm shunt resistor. That converts back to a peak-to-peak input voltage of 11.25 Vpp (the datasheet expresses this voltage as 5.62 V peak which is the same thing. So if you are applying input signals down to 10 Hz, you will need a large ac-coupling cap and should not apply a signal to that cap that is bigger than 11.25Vpp (you may or may not choose to have an external shunt resistor; you only need this if you want to implement 50 ohm matching).

Now to ADL5511. The same thing applies here but the max voltage is 5.6 Vpp applied to a externa ac-coupling capacitor.

If you are asking for the absolute max voltages that you can apply directly to the pins, that is a more difficult question. It is not typical to dc-couple the inputs on any of these parts because the RF input pin has an internally-set working bias voltage level. The actual max voltage at the RFIN pins will be 11.25Vpp (ADL5904,ADL5910) or 5.6Vpp(ADL5511) but centered on this internally set bias voltage.

Let me know if I've answered your questions. - Eamon

enash · Answer

Your 2V pp signal will be ac-coupled into the ADL5511. So don't think of it as having a minimum level of -1V. I don't know the exact bias level at the RFIN pin of ADL5511 but let's say, it is mid-supply, that is, 2.5V. So your 2Vpp signal will take the voltage at the RFIN pin from 3.5V to 1.5V. This will not damage the IC.

enash · Answer

Your 2V pp signal will be ac-coupled into the ADL5511. So don't think of it as having a minimum level of -1V. I don't know the exact bias level at the RFIN pin of ADL5511 but let's say, it is mid-supply, that is, 2.5V. So your 2Vpp signal will take the voltage at the RFIN pin from 3.5V to 1.5V. This will not damage the IC.

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The input range for ADL 5904 5910 and ADL 5511